A memory system using nonvolatile semiconductor memories such as a memory card may transmit and receive a large volume of data such as image data or voice data to and from a host. In these applications, it is required to read or write a lot of information in a shorter time, that is, to make the data transfer speed higher. Conventionally the host and the card have been connected by board wiring or a cable, but because the physical characteristics of the wiring or cable have a greater influence as the speed becomes higher, it is becoming difficult to implement.